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Fri, 03 Dec 2021 18:14:58 +0000 Date: Fri, 3 Dec 2021 18:14:58 +0000 From: Matthew Wilcox To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/2] mm: move filemap_range_needs_writeback() into header Message-ID: References: <20211203153829.298893-1-axboe@kernel.dk> <20211203153829.298893-2-axboe@kernel.dk> <5e92c117-0cdb-9ea6-3f1c-912e683c4e51@kernel.dk> <89810ae4-7c9b-ec8f-5450-ef8dc51ad8a4@kernel.dk> <97e253f7-d945-0c6b-3d8b-dcf597f04f69@kernel.dk> <9cabdcc3-e760-bab5-edfe-ae225e5d4db9@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9cabdcc3-e760-bab5-edfe-ae225e5d4db9@kernel.dk> X-Stat-Signature: txma59reo1zzubfh1fq9iigmni4u8mpn Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=iYFrG4xr; spf=none (imf02.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: EA50280006 X-HE-Tag: 1638555300-743128 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Dec 03, 2021 at 11:01:14AM -0700, Jens Axboe wrote: > On 12/3/21 10:57 AM, Jens Axboe wrote: > >> I'm happy with this, if you just move it to pagemap.h > > > > OK, I'll try it out. > > Wasn't too bad at all, actually just highlighted that I missed removing > the previous declaration of filemap_range_needs_writeback() in fs.h > I'll do a full compile and test, but this seems sane. > > commit 63c6b3846b77041d239d5b5b5a907b5c82a21c4c > Author: Jens Axboe > Date: Thu Oct 28 08:47:05 2021 -0600 > > mm: move filemap_range_needs_writeback() into header > > No functional changes in this patch, just in preparation for efficiently > calling this light function from the block O_DIRECT handling. > > Signed-off-by: Jens Axboe Reviewed-by: Matthew Wilcox (Oracle) > diff --git a/include/linux/fs.h b/include/linux/fs.h > index bbf812ce89a8..6b8dc1a78df6 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -2847,8 +2847,6 @@ static inline int filemap_fdatawait(struct address_space *mapping) > > extern bool filemap_range_has_page(struct address_space *, loff_t lstart, > loff_t lend); > -extern bool filemap_range_needs_writeback(struct address_space *, > - loff_t lstart, loff_t lend); > extern int filemap_write_and_wait_range(struct address_space *mapping, > loff_t lstart, loff_t lend); > extern int __filemap_fdatawrite_range(struct address_space *mapping, > diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h > index 605246452305..274a0710f2c5 100644 > --- a/include/linux/pagemap.h > +++ b/include/linux/pagemap.h > @@ -963,6 +963,35 @@ static inline int add_to_page_cache(struct page *page, > int __filemap_add_folio(struct address_space *mapping, struct folio *folio, > pgoff_t index, gfp_t gfp, void **shadowp); > > +bool filemap_range_has_writeback(struct address_space *mapping, > + loff_t start_byte, loff_t end_byte); > + > +/** > + * filemap_range_needs_writeback - check if range potentially needs writeback > + * @mapping: address space within which to check > + * @start_byte: offset in bytes where the range starts > + * @end_byte: offset in bytes where the range ends (inclusive) > + * > + * Find at least one page in the range supplied, usually used to check if > + * direct writing in this range will trigger a writeback. Used by O_DIRECT > + * read/write with IOCB_NOWAIT, to see if the caller needs to do > + * filemap_write_and_wait_range() before proceeding. > + * > + * Return: %true if the caller should do filemap_write_and_wait_range() before > + * doing O_DIRECT to a page in this range, %false otherwise. > + */ > +static inline bool filemap_range_needs_writeback(struct address_space *mapping, > + loff_t start_byte, > + loff_t end_byte) > +{ > + if (!mapping->nrpages) > + return false; > + if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && > + !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) > + return false; > + return filemap_range_has_writeback(mapping, start_byte, end_byte); > +} > + > /** > * struct readahead_control - Describes a readahead request. > * > diff --git a/mm/filemap.c b/mm/filemap.c > index daa0e23a6ee6..655c9eec06b3 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -646,8 +646,8 @@ static bool mapping_needs_writeback(struct address_space *mapping) > return mapping->nrpages; > } > > -static bool filemap_range_has_writeback(struct address_space *mapping, > - loff_t start_byte, loff_t end_byte) > +bool filemap_range_has_writeback(struct address_space *mapping, > + loff_t start_byte, loff_t end_byte) > { > XA_STATE(xas, &mapping->i_pages, start_byte >> PAGE_SHIFT); > pgoff_t max = end_byte >> PAGE_SHIFT; > @@ -667,34 +667,8 @@ static bool filemap_range_has_writeback(struct address_space *mapping, > } > rcu_read_unlock(); > return page != NULL; > - > -} > - > -/** > - * filemap_range_needs_writeback - check if range potentially needs writeback > - * @mapping: address space within which to check > - * @start_byte: offset in bytes where the range starts > - * @end_byte: offset in bytes where the range ends (inclusive) > - * > - * Find at least one page in the range supplied, usually used to check if > - * direct writing in this range will trigger a writeback. Used by O_DIRECT > - * read/write with IOCB_NOWAIT, to see if the caller needs to do > - * filemap_write_and_wait_range() before proceeding. > - * > - * Return: %true if the caller should do filemap_write_and_wait_range() before > - * doing O_DIRECT to a page in this range, %false otherwise. > - */ > -bool filemap_range_needs_writeback(struct address_space *mapping, > - loff_t start_byte, loff_t end_byte) > -{ > - if (!mapping_needs_writeback(mapping)) > - return false; > - if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && > - !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK)) > - return false; > - return filemap_range_has_writeback(mapping, start_byte, end_byte); > } > -EXPORT_SYMBOL_GPL(filemap_range_needs_writeback); > +EXPORT_SYMBOL_GPL(filemap_range_has_writeback); > > /** > * filemap_write_and_wait_range - write out & wait on a file range > > -- > Jens Axboe >